Sigillaria, An Ancient Tree
Sigillaria is the generic name assigned to this ancient arborescent lycopod. Occassionally the trunks were smooth. Extinct genus of tree-sized lycopsids from the Carboniferous Period (about 360 to 300 million years ago) that are related to modern club mosses. Sigillaria had a single or sparsely branched trunk characterized by a slender strand of wood and thick bark.
Winchell, Alexander Sketches of Creation (New York, NY: Harper & Brothers, 1870)